Hello,
On Sunday 12 April 2009 21:08:31 you wrote:
> On Sat, 11 Apr 2009 18:16:14 +0400
>
> Victor <ErV2005@xxxxxxxxxx> wrote:
> > Hello.
>
> Hello Victor,
>
> > I'm using Genius E-Messenger 112 webcam on Slackware 12.2 with
> > 2.6.27.7 kernel (custom-built) and yesterday's v4l-dvb sources
> > checked out via "mercurial" ("hg log" returns "11445:dba0b6fae413" as
> > latest commit). the camera uses gspca_main and gspca_pac207 kernel
> > modules.`
> >
> > Camera works (with LD_PRELOAD=v4l2convert.so) in mplayer (mplayer
> > tv://) and skype, but picture is way too dark. It looks like
> > "contrast" is permanently set at maximum, and doesn't change
> > (although it looks like camera tries to adjust brightness
> > automatically).
> >
> > How can this be fixed?
>
> Did you try to change the webcam controls? (there are brightness,
> exposure, autogain and gain - they may be changed by programs as
> v4l2ucp or vlc)
I can modify brightness, exposure, gain/autogain from vlc.
It looks like the problem is related to automatic gain function. Automatic
gain is enabled by default. When it is enabled, it slowly sets "gain" to the
maximum, "brightness" to minimum, and "exposure" according to the situation
(somewhere in the middle).
"Normal" results are produced when gain is near zero.
That's why picture looks bad.
I could run vlc each time I'm going to use webcam, of course, but I'd like to
keep automatic brightness/contrast/gain feature and fix it.
As I understand it, automatic exposure is handled by
"gspca_auto_gain_n_exposure" routine which is located at line 2048 in gspca.c,
but "gspca_auto_gain_n_exposure" is actually called
from "pac207_do_auto_gain", line 338 of pac207.c, and at least some data that
could produce wrong result (avg_lum) seems to be read from the frame data of
the webcam (line 385 of pac207.c).
So I'm not quite sure - given this info,
> You may ask to Hans de Goede who is the maintainer of the pac207
> driver.
>
> Cheers.
should I continue discussion here or contact maintainer of pac207 instead?
--
Best regards, Victor
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